Gradient glowing object - how to?
Where exactly are you trying to export to and through which exchange format?
As stated above materials are very tied to the rendering system they were created for, you can't really export them as you can with a 3D model.

If you are using Cycles render you need to


Create a new material
Add two emission shaders (one with the desired color, the other white)
Use a Mix Shader node to mix them
Add a layer weight node as mixing factor
You may use either Fresnel or Facing as output
Optionally you can fine tune the color grading with a Vector Curve Node
To get the material to emit light only in one color add a new Mix Shader node
Connect the original shader to the bottom socket
Connect the uniform emission color to the top socket
To control that mix shader add a Light Path node
Connected the Is camera socket to the mix factor




This should work in Cycles, but as stated above it is very much tied to the way Blender works and how Cycles builds it's shaders, I very much doubt you will be able to export this anywhere useful, much less to a real time rendering system like a game engine or something.